On Tue, Jul 14, 2026 at 09:06:55PM +0800, Zhanpeng Zhang wrote: > The RISC-V IOMMU QoS extension provides iommu_qosid as a per-IOMMU > global default tag. It is used for IOMMU-originated DDT, CQ, FQ, PQ, and > MSI accesses, and for device-originated requests when DDTP is in BARE > mode. > > Initialize iommu_qosid to RCID 0 and MCID 0 when the hardware advertises > QOSID support. Preserve reserved and WPRI bits with read-modify-write, > and use register readback to reject values which the WARL fields do not > retain. > > Add a qosid attribute to the RISC-V IOMMU class device. Reading returns > the current RCID and MCID values. Writing the documented > 'rcid=<rcid> mcid=<mcid>' form updates both fields while preserving the > other register bits. > > Keep this interface separate from resctrl group QoS. The sysfs attribute > controls the IOMMU-wide default, while resctrl device assignment programs > per-device DC.ta in translated modes. > > Signed-off-by: Zhanpeng Zhang <[email protected]> > --- > .../ABI/testing/sysfs-class-iommu-riscv-iommu | 27 +++ > MAINTAINERS | 10 ++ > drivers/iommu/riscv/iommu.c | 159 +++++++++++++++++- > drivers/iommu/riscv/iommu.h | 9 +- > 4 files changed, 202 insertions(+), 3 deletions(-) > create mode 100644 Documentation/ABI/testing/sysfs-class-iommu-riscv-iommu [..] > diff --git a/drivers/iommu/riscv/iommu.h b/drivers/iommu/riscv/iommu.h > index 2c57625637bf..13ea67b7e42d 100644 > --- a/drivers/iommu/riscv/iommu.h > +++ b/drivers/iommu/riscv/iommu.h > @@ -12,8 +12,12 @@ > #define _RISCV_IOMMU_H_ > > #include <linux/iommu.h> > -#include <linux/types.h> > #include <linux/iopoll.h> > +#include <linux/mutex.h> > +#include <linux/types.h> > +#ifdef CONFIG_RISCV_IOMMU_32BIT > +#include <linux/spinlock.h> > +#endif
RISCV_IOMMU_32BIT does not seem to exist upstream and these lines to just be deleted later in patch 6. Drew
